Conventionally, for instance, as a centrifugal pump to cool a small machine such as a cooling water of comparatively small machine such as a personal computer, a computer server and a printer, as described in Patent Document 1 (JP 2003-13878, A), a centrifugal pump is disclosed.
The centrifugal pump in Patent Document 1 is a centrifugal pump, in which a structure of an impeller is improved to form a plurality of passage portion that is radially extended from the center thereof where the fluid is flown.
As a result, the circulation volume change of cooling water is a little and the change in the cooling capability is hardly occurred.
Moreover, in Patent Document 2 (JP 2003-161284, A), an impeller is formed such that a multitude of blade is formed on the outer periphery and a rotor magnet is provided on the inner periphery, and a motor stator is disposed on the inner periphery side of the rotor magnet.
As a result, a thin centrifugal pump that can achieve an efficient cooling while attaining reducing the thickness is disclosed.